January 12, 1905] 



NATURE 



247 



OVR BOOK SHELF. 



La Statique chimique basee sur les deux Principes 



fondamentaux dc la Thermodynaniique. By E. 



Aries. Pp. vui + 251. (Paris: A. Hermann, 1904.) 



Price 10 Irancs. 

 Die heterogenen Gleichgewichte vom Standpunkte der 



Phasenlehre. Zweites Heft, erster Tail. By H. W. 



Bakhuis Roozeboom. Pp. xii + 467. (Brunswicli : 



F. Vieweg and Son, 1904.) Price 12.50 marlis. 

 The two volumes under review are concerned with 

 the application of thermodynamics to the problems of 

 g;eneral chemistry, but are yet so different in material 

 and in treatment that few points of resemblance may 

 be found between them. 



In the book by Lieut.-Colonel Aries the mathe- 

 matical derivation of the laws of equilibrium from 

 the fundamental principles of thermodynamics are 

 stated in the most abstract and general form with just 

 sufficient exemplification to indicate tlie bearing of the 

 deductions on the practical work of physical chemistry. 

 The author uses as characteristic function tlie thermo- 

 dynamic potential at constant pressure, and it may be 

 said in a word that his deductions are as simple and 

 concise as the case will allow, the introduction of use- 

 less conceptions and formulse being scrupulously 

 avoided. One noteworthy feature which might with 

 advantage be imitated in other works on thermo- 

 dynamics applied to chemistry is the postponement of 

 the discussion of the perfect gas to a point in the last 

 third of the volume. The student is only too apt in 

 dealing with the involved formulae of certain cases of 

 chemical equilibrium to introduce unconsciously into 

 his equations some result which has its origin in a 

 consideration of perfect gases, thereby obtaining a 

 simple result apparently general, but in reality not so. 

 The temptation to do this is greatly lessened by the 

 simplification of the perfect gas being delayed 

 until the general formulae are well developed. The 

 book is well and clearly written, and those interested 

 in mathematical chemistry will be thankful for this 

 lucid exposition of the subject. 



The first part of Prof. Roozeboom 's book has already 

 been noticed in Nature. It dealt with the equilibria 

 of systems of one component. The present volume 

 deals with the equilibria of binary systems, though 

 such is the wealth of material that it has been found 

 necessary to reserve the discussion of many systems 

 presenting special features for a subsequent volume. 

 In contradistinction to the work of Colonel Aries, there 

 is scarcely a mathematical formula to be found in Prof. 

 Roozeboom 's treatise; the graphic method is used to 

 the practical exclusion of others. In the present part 

 there are 150 diagrams, chiefly of curves the co- 

 ordinates of which are pressure, volume, temperature, 

 and composition in some combination. As in the first 

 part, the various equilibria are carefully classified 

 according to the nature of the phases involved, and 

 each class is discussed in detail with the most pains- 

 taking completeness, and with full reference to the 

 original sources of the experimental work used in illus- 

 tration. In general terms the volume may be said to 

 deal with simple solutions, and no one whose interest 

 lies in this direction can afford to dispense with the 

 aid of such a valuable guide to the work already 

 accomplished, and to the theory of the practical work 

 still to be performed. ' J. W. 



Tlie Timbers of Commerce and their Identification. 



By H. Stone. Pp. xxviii + 311. (London : William 



Rider and Son, Ltd., 1904.) Price 7s. 6d. net. 



This work is sure to meet with a cordial reception 



and to be welcomed by all branches of the timber trade. 



The information contained in its pages is such that 



only an enthusiast and expert could' bring together 



NO. 1837, VOL. 71] 



with the cooperation of others fnterested in the growth 

 and utilisation of timber in every part of the globe. 

 In all 247 different species are described, even to the 

 minutest detail. In each case the specific name and 

 authority are stated, and, wherever necessary, to avoid 

 confusion, the synonyms have also been added. Then 

 comes a list of the alternative names, or what we 

 might call the common names. It is a well known 

 fact that frequently one and the same kind of timber 

 receives two different names, whereas two totally 

 different species may be known by the same common 

 name. The vernacular names in foreign languages, 

 so far as they are not to be found in dictionaries, have 

 also been quoted. Following this comes a paragraph 

 dealing with physical characters, &c., such as recorded 

 dry weight, hardness, taste, combustion, character of 

 ash constituents, &c. The grain and bark are next 

 described. The following paragraph deals with the 

 uses to which the timber may be put. The colour is- 

 also given as a means of identification, and the 

 anatomical characters, as seen in transverse and longi- 

 tudinal sections, are fully described. 



The author seems to have spared no pains in collect- 

 ing and authenticating the vast amount of information 

 and details necessary for the above purpose. A very 

 valuable feature of the book are the illustrations, 

 numbering 183 photomicrographs, which represent all 

 the genera mentioned in the text, except where a single 

 illustration serves for more than one genus. In most 

 cases the photographs are taken from transverse 

 sections, though in many cases longitudinal sections 

 are also given. It is stated that the scale of magnifi- 

 cation is three times the actual size, and is designed 

 to show the appearance of a transverse section as seen 

 by means of an ordinary hand lens. For those de- 

 siring further general information about wood a very 

 useful bibliography is given at the end of the book. 

 .'Klso two appendices are added, which respectively 

 describe the method and apparatus for measuring the 

 amount of resistance in timber to impact and the 

 absorption of water by a given area on any surface of 

 a piece of wood. 



At the beginning of the book a very interesting 

 chapter, entitled " Practical Hints," is included, which 

 we are sure will be read with much interest and profit 

 by all those who work with wood. The index is a 

 very complete one, and will render the book invaluable 

 as a ready work of reference. 



Verhandliingen der deutschen zoologischen Gesell- 

 schaft, for 1904. Pp. 252 ; illustrated. (Leipzig : 

 Engelmann.) Price lis. net. 

 This "valuable publication contains the papers read at 

 the twenty-fourth annual meeting of the society, held' 

 at Tubingen on May 24-26, 1904. The congress was 

 opened by an address from Prof. Spengel, in which the 

 society was congratulated on the good work it cori- 

 tinued to produce, and especially on recent investi- 

 gations on the structure of the Protozoa and on the 

 relations of the nucleus to the general mass of proto- 

 plasm. To Prof. Blochmann was assigned the 

 pleasant task of welcoming the society to Tubingen. 

 The published papers are sixteen in number, in addition 

 to which were numerous exhibits and demonstrations. 

 Most of the former are of an extremely technical 

 character, and to a large extent interesting chiefly to 

 specialists. Among them we may refer to Prof. A. 

 Brauer's account of recent investigations into the 

 structure of the light-organs of the bony fishes, more 

 especially of the deep-sea forms, in which the question 

 of the relation of these structures to the lateral line 

 system is discussed at considerable length. Dr. von 

 Buttel-Reepen's article on the mode in which the larvae 

 of the honey-bee are made to assume a particular sex 

 is also one of considerable importance. In the courser 



